I believe Darth Nox would be able to defeat the Wrath. For one, so long as Darth Nox has the Sith ghosts inside of him/her, they are unkillable (although if their head was chopped off that might hinder them a little). Also, Nox already had a strong connection to the Force, but the ghosts increased the connection a hundred fold. The Wrath needs to get close to Nox to maximize damage output with his lightsaber, but that is difficult when Nox is shielded by lightening and when Nox is zapping the Wrath with electricity. It may not be fair, but then again, Nox and the Wrath are Sith lords, they aren't supposed to play fair. Also, would we be including companions into this epic battle?